公开(公告)号：US5047469A

公开(公告)日：1991-09-10

申请号：US307949

申请日：1989-02-09

申请人： Takanori Kitamura ,  Yuuji Takenouchi ,  Kunio Abe

发明人： Takanori Kitamura ,  Yuuji Takenouchi ,  Kunio Abe

IPC分类号： C08F8/12 ,  C08F16/00 ,  C08F16/06

CPC分类号： C08F8/12

摘要： The polyvinyl alcohol of the present invention is a partially saponified polyvinyl alcohol having a saponification degree of 70 to 98 mol % and containing a larger amount of methanol-soluble substances than that contained in polyvinyl alcohols having the same saponification degree obtained by known processes, and is novel.And, the process for producing polyvinyl alcohol of the present invention comprises saponifying polyvinyl esters in a solvent of a polyoxyalkylene ether having in the molecule thereof a structural unit represented by the general formula [I]:--O).sub.l (R.sup.1 --O).sub.m (R.sup.2 --O).sub.n [I]wherein R.sup.1 and R.sup.2 each represents an alkylene group having 2 to 5 carbon atoms in the main chain thereof, which may be substituted with a lower alkyl group or lower alkoxy group; l is an integer of 0 or 1; m and n each represents 0 or an integer of 1 to 10; and l+m+n.gtoreq.2; with the catalyst of an aliphatic or aromatic sulfonic acid at an elevated temperature in the presence of water. The process can produce polyvinyl alcohol having a higher saponification degree at a higher reaction rate than conventional hydrolysis processes catalyzed by acids.